nVision connection not being load-balanced

Most of our PeopleSoft users are located in our head office and use a two-tier connection for nVision (for performance reasons).  Our remote users (non-head office) all use three-tier connections.  Recently, we became aware that the connection for one of our remote users was not being load-balanced--one of the two application servers was down, and the connection was not re-directed to the other app server.  Where in the workstation configuration file do we need to modify the settings to use the load-balancing features of the app servers?